Fresh from overseeing Tesco’s expansion into the United States, Sir Terry Leahy is quick to dismiss speculation that the milestone could trigger a decision to call time on one of the most successful careers in British business.

Despite a decade spent transforming the supermarket group from Britain’s No 2 into one of the world’s most powerful retailers, the chief executive insists the challenge has only just begun.

The 51-year-old wants to lay the foundations to ensure Tesco reaches a target of generating more than half its turnover from overseas within the next five to ten years. At present, less than a third of Tesco’s annual sales of around £50 billion come from international operations.

“There may be bigger companies, but there’s none better,” Sir Terry said. “We are on the threshold of becoming one of the few successful international retailers. The challenge is larger, it’s not getting smaller. There’s plenty to do.”

Many would argue that Tesco has already more than succeeded on the global stage. On top of taking £1 in every £8 spent by shoppers in the UK, the group runs sizeable operations in 12 countries outside Britain, with an empire that stretches from the Republic of Ireland via Poland and on to Thailand and China.

International sales this year should top £13 billion, equal to Tesco’s total turnover at the time that Sir Terry took over in 1997. “We have created another Tesco in ten years,” he said. Moreover, this month the group made its boldest move yet by opening its first food store in the United States, after three years of research. So far, 13 of the neighbourhood, convenience-style stores are up and running in Los Angeles, Las Vegas and San Diego under the green and white Fresh & Easy banner.

A total of 50 Fresh & Easy stores are due to be opened by February under the management of Tim Mason, the former marketing director tipped as a possible successor to Sir Terry in the boardroom back home.

The small stores – typically one fifth the size of a British supermarket at 10,000 sq ft – are targeting the “top-up” market with a combination of ready meals, fresh food and leading brand items, such as Kleenex and Tide detergent.

Industry experts claim that Tesco officials are already swarming the East Coast of America to check for potential locations in New York and Florida. Sources in the US have also been quoted as saying that Tesco is searching Chicago for a site to open a distribution centre.

The rumour mill reflects the buzz around what some have called the biggest event in world retailing this year. Sir Terry takes it in his stride. He will say only that customer and staff reaction in the US has been “very good” since the first store opened in Hemet, east of LA, three weeks ago. However, he admits that the key to Tesco succeeding where other notable British rivals, such as Marks & Spencer and J Sainsbury, have failed is opening as many of the stores as quickly as possible. “You can’t afford to trial in America,” he said. “You go from the outset or else you get copied.

“There’s no secrets in retail. If you look at successful retail companies over the the years, what has characterised them is the fact they move at a fast pace. I think if you were still struggling to tweak a concept after four years, you would not have a success on your hands.

“For a variety of reasons, in the past British retailers have not been able to follow through what they have started, things have gone wrong at home and they have not been able to sustain the effort.

“But the potential is huge. Good retailers in the US have made good returns. It’s just a bit of a graveyard for all the others who are not successful.”

Despite the interest from the media and the industry, Sir Terry is keen to emphasise that the attempt to succeed in Wal-Mart’s backyard is only part of the bigger picture. The targets that the group has set to generate far bigger sales from its international division are also likely to rely on expansion into India and Russia.

He also refuses to rule out future acquisition activity, although he insists that through organic growth alone Tesco should hit the goals he has set over the next decade. “We have got some pretty ambitious internal targets for growth. The US is an important part, but it is by no means the majority.”

If Tesco’s international business “comes of age” as Sir Terry hopes, the Liverpudlian is in line for a windfall. A long-term incentive plan heavily skewed to success in the US could pay out up to £11.5 million from 2011. Analysts point out that this is likely to mean that he remains at Tesco’s Cheshunt head office for at least four years. One told The Times: “He’s not going anywhere until that begins to vest.”

Debate over a potential succession plan has been sparked this year by a steady flow of departures from Tesco’s senior management. Observers have talked of a “brain drain” at Tesco, given the loss of executives such as Julia Reynolds, the Central European clothing boss, who last month left to join Figleaves.com, the online lingerie retailer. Her departure came hot on the heels of Dido Harding, who left her post as a senior director on the leadership development programme to join Sainsbury’s as head of its convenience store operations. John Browett, operations and IT development director, left in June to take over as chief executive of DSG International.

Rather than proof of a glass ceiling at Tesco, Sir Terry sees the departures as confirmation of the strength in depth in his senior team. This strength has been critical in helping him over the past ten years.

He admits that the ability to delegate has been key to allowing him to spend time “learning” by talking to customers and “collecting more knowledge” in the industry. “When stories have been written about people leaving, they have named a maximum of four or five people that have left from Work Level 5 and four or five that have left from Work Level 4. These people have gone over three years and from a population of 460 across Work Level 5 and 4. We have employed far more people than have gone.

“I had a team-build the week before last, my team was 70 people, doing jobs all over the world. All of them are talented people and any one of them could run a company.

“Tesco is not a brutal place. We don’t go executing people in public and it’s not one of those things where people flounce off or walk the plank. Often it’s by mutual consent.”

He put forward a further explanation for the departures: “The first company a headhunter goes after is Tesco. Everyone wants a Tesco person in their team. The more people that go through Tesco to somewhere else, the more we can attract in the future.”

Curriculum vitae

Born: February 28, 1956
Education: St Edwards College, Liverpool, and then the University of Manchester Institute of Science and Technology, where he gained his BSc (Hons) in management sciences
Career: Joined Tesco in 1979 as a marketing executive and was promoted to marketing manager in 1981. From 1984 to 1986 he was marketing director for Tesco Stores Ltd. He was made commercial director of Fresh Foods in 1986. Joined the board of Tesco plc as marketing director in 1992 and was made deputy managing director in February 1995. Became chief executive in March 1997. Received a knighthood for services to food retailing in the 2002 New Year Honours
Family: Married with three children
Other interests: Enjoys sport, reading, theatre and architecture in his spare time. He is a director on the Liverpool Vision Regeneration Board and Co-Chancellor of Manchester University

The leader questioned

If you could change one thing in the financial and commercial environment, what would it be?

Currently, interest rates. Consumers and businesses need a break, having had a tough year with rising energy costs and increasing mortgage payments. I’m hopeful we will see a cut from the Bank of England next time around.

Who is or was your mentor?

There have been many influential people that have had a positive impact on me over the years, especially at Tesco. David Malpass, a former managing director and my predecessor Ian McLaurin, to name two.

Does money motivate you?

Everybody strives to provide as well as they can for their families and money is always a factor in that. My greatest motivation is in helping thousands of families to lead a better life by providing them with better and more affordable shopping.

What is the most important event to happen in your working life?

It has to be moving south to work for Tesco. If I hadn’t, I might be running the Coop.

What gadget must you have?

I’m not a great one for gadgets, preferring face-to-face conversation to e-mails and mobile phones. There really is no substitution for chatting to people in person.

What does leadership mean to you?

I think of it as enabling people to achieve more than they could on their own. In a practical sense this means having vision, leading by example, motivating and inspiring.

Which business person do you most admire?

Procter & Gamble’s chief A. G. Lafley. He is low-key but very focused and good on strategy.

How do you relax?

Spending time with my family is important. My passion for Everton and football is also well known (including a link with its new stadium scheme in Kikby) but it’s not always very relaxing.